Manufacture of linoleum



A118. J. L BERGER 2,425,719

MANUFACTURE OF LINOLEUM Filed Sept. 19, 1942 Patented Aug. 19, 1947MANUFACTURE OF LINOLEUM John L. Berger, Columbia, Pa., assignor to-Armstrong Cork Company, Lancaster, Pa., a corporation of PennsylvaniaApplication September 19, 1942, Serial No. 458,947

This invention relates to the manufacture of linoleum and, moreparticularly, to the production of molded inlaid linoleum and the likein which the pattern is formed essentially of inlays initially ofgranulated inlaying composition compacted into a homogenous mass onto asuitable backing such as burlap or waterproofed felt and subsequentlycured.

Molded inlaying composition is generally formed of oxidized oil andresin, intimately mixed with a filler such as cork or wood flour andsuitable pigments. The particles or granules of inlaying composition aresticky in the sense that if a handful of the mix is compressed, it willball or cohere. The mix is, however, when in its loose condition,suificiently free flowing to permit strickling through small stencilopenings.

In the manufacture of molded inlaid linoleum, a backing of burlap is fedover an inlaying table under a series of stencils and granulatedinlaying composition is strickled through the stencils onto the backingindesign, each stencil serving to define the outline of an inlaid area.of a separate color. As the material moves through the machine past thecomplete set of stencils, the entire surface of the backing is coveredwith inlaying composition. The composition is in a relatively loosecondition and is subsequently subjected to heat and high pressure, inthe neighborhood of 350 F. and 1450 pounds per square inch, toconsolidate it into a wear resisting surface of the desired finalthickness, properly keyed to the burlap or other foundation. Heatedplaten hydraulic presses are generally used for this purpose.

In the pressing operation, considerable difliculty has been occasioneddue to the adherence of the granulated inlaying composition to theplaten of the hydraulic press which engages it in initial heatconsolidation. If the adhesion is great, whole areas of the inlayingcomposition will be pulled away from the backing and other areas will beloosened from the backing. Even when there is only slight adherence overthe whole face of the composition, the parting of the press platenscauses a loosening of the inlaying composition from the backing and apoor key results in the finished product.

One method commonly used with considerable success and obviating to someextent at least the problem involved has been the use of a web of oiledpaper applied over the upper platen of the first press. A fresh portionof the oiled paper is presented at each pressing operation. Whilethisprecludes sticking of the composition to the press 9 Claims. (Cl.154-26) platen, it has been objectionable for a number of other reasonsprimary, among which is the fact that even with oiled paper there is aslight adherence of the inlaying composition onto the oiled paper underthe high pressure and temperature conditions'of consolidation so thatwhen the oiled paper is stripped from the face of the composition, athin film or skin of composition is pulled from the face of thecompacted mass and this reduces the smoothness of the upper surface andalso tends to pull the composition away from the backing, loosening thekey. Besides, the paper is relatively expensive and can be used but a.single time.

Another method which has been tried without any substantial success isto spray the loose granular inlaying composition with a mist oflubricant. This was done immediately prior to initial consolidation.This practice was unsuccessful primarily because the lubricant preventedproper binding of the granulated mix into a homogeneous mass. The binderand the lubricant are not compatible and, since the mass is relativelyopen and porous, the application of a spray of lubricant to the surfacehas resulted in penetration of the lubricant through a substantialportion of the thickness of the layer of inlaying composition and thishas reduced the internal bond of the particles to the depth ofpenetration of the lubricant.

Theapplication of an oil film to the face of the upper platen of thepress has been tried but the problems of uniform distribution of alubricant to the face of a large heated platen hydraulic press aremanifold and this method has never been commercially practiced.

According to this invention, the upper surface only of the loosegranulated inlaying composition is coated with a lubricant prior toinitial consolidation of the mass. Thus, the application of thelubricant is limited to-those surfaces of the particles which will beengaged by the pressing surface. This is preferably accomplished byengaging the loose inlaying composition with a web of fabric,such asmuslin or scrim cloth, which has been saturated with a lubricant. Onlya'relatively slight pressure is applied, sufficient to [insureengagement between the lubricant-saturated fabric and the upper surfaceof the particles, but insuificient to cause particles of the linoleumcomposition to adhere to the fabric. An extremely thin film of lubricantis transferred to the upper surface of the particles at the face of theinlays.

It is not necessary that heat be applied at this stage and it ispreferred not to apply heat until initial consolidation is eifected.Since the movement of the material through the inlaying machine isintermittent, the lubricant is preferably applied by an intermittentlyoperating device.

In order that the invention may be more clearly understood, referencewill be made to the accompanying drawing in which:

Figure 1 is a diagrammatic view showing an apparatus in conventionalform for carrying out the method of this invention; and

Figure 2 is a diagrammatic view of a modified consolidating pressutilized in carrying out a modification of my method.

Referring to the drawing, the forward end of a molded inlaying machineis shown. This includes the usual table 3 and pin band conveyor 4. Theconveyor is intermittently operated to draw the backing through themachine into the various stencilling stations. The material as itemerges from the inlaying machine, as shown in Figure l, is formed of abacking 5, shown diagrammatically as a single line, having a layer 6 ofgranulated inlaying composition thereon, preferably formed of inlays ofdifferent colors, although the material may be monocolored or of thegranite type having two or more colors randomly interspersed.

In regular manufacture, the material passes from the inlaying machine toa press 1 where initial heat consolidation is effected. The upper platen8 of the consolidating press 1 is normally covered with an oiled paperto prevent adhesion, as previously pointed out. According to thisinvention, there is disposed between the initial heat consolidatingpress 1 and the point where the stencilling and inlaying is completed adevice 9 for applying lubricant to the upper surface of the particlesforming the layer 6 of inlaid composition. In the embodimentdiagrammatically illustrated, this takes the form of a plate I having afiat lower surface over which is stretched a fabric such as muslin orscrim cloth H, saturated with a suitable lubricant. Parafiine oil is thepreferred lubricant, but other lubricants may be substituted for it. Thefabric is fed from a wind-up roll l2, over the plate ID to a wind-uproll IS. A hand crank I4 is shown by which the winding may beconveniently effected. Generally, a fresh area is presented at each stepto insure a uniform application of the lubricant to the surface and whenthe fabric has all been reeled onto the wind-up l3, the roll isresaturated with the lubricant and the operation of the wind-ups isreversed, the roll l2 now serving as a wind-up. A hand crank I5 isprovided on the wind-up roll l2 for this purpose.

To bring the lubricant-saturated fabric into engagement with the uppersurface of the particles, there is shown for purposes of illustration acam l6 engageable with a cam follower ll mounted upon a support for theplate I0. The operation of the cam I6 is synchronized with the movementof the pin conveyor 4 to bring the device 9 down into engagement withthe composition 6 at each stencilling operation'and while the materialis at rest on the inlaying table 3.

No substantial pressure is applied by the device 9; sufficient isapplied to insure a satisfactory transfer of lubricant from the fabricII to the surface of the composition 6 uniformly over the whole treatedarea. Satisfactory results have been obtained when the pressure has beenlimited to about one and one-half pounds per square inch but this willvary depending upon the type of lubricant employed, the physical make-upof the 4 fabric, and the tackiness of the inlaying composition beingoperated upon, The lubricant should be of such nature and transferred insuch amount that the surface only of the particles forming the uppersurface of the layer is coated, but this coating should be complete toprevent adherence of untreated particles to the platen 8 in initial heatconsolidation.

The material with lubricant applied to the upper surface is then heatconsolidated and cured in the usual manner. My method finds particularusefulness in the high temperature-low pressure initial consolidationand a final low temperature-high pressure facing or finishingconsolidation. This method is diagrammatically illustrated in Figure 1where press 1 has the upper platen 8 and the lower platen [8 each heatedto about 350 F. A pressure of about pounds per square inch is appliedfor a period of about six seconds with a typical linoleum mix. The webattains a temperature of about 280 F. during this initial consolidation.The composition is reduced in thickness and consolidated to some extentand the high temperature causes the binder for the composition to flowto a considerable extent. The pressing surface is highly polished and ispreferably a chromium plated steel platen. Even with this hightemperature treatment, there is no offsetting or sticking of thecomposition to the press platen 8. As previously pointed out, it hasbeen customary practice to cover the press platen 8 with a web of oiledpaper to prevent this adherence and the disadvantages of such practicehave been stated above. With my method this is completely eliminated.

The consolidated material then passes to a facing press [9 having anupper platen 2U heated to about 240 F. The lower platen 2| is heated byconduction from the heat in the composition and normally attains atemperature of about 180 F. A heated plate 22 may be interposed betweenthe presses I and 19 to maintain the desired temperature in thecomposition, about 230 F. The facing press applies a pressure of about1450 pounds per square inch to the composition, reducing it to finalthickness, giving it a high gloss face, and keying it securely to thebacking. The dwell of the facing press 19 is about six seconds and theconsolidated web maintains its temperature at about 230 F. during thispressing operation.

The finally consolidated material is fed to a curing stove or oven formaturing in the customary manner.

In Figure 2, I have illustrated a press of modifled construction for theinitial heat consolidation. It will be noted that the forward end 23 ofthe upper platen 24 of the press is flared at 25. It is customary toprovide the lower platen 26 with a pad of cushioning material which issimilarly flared as shown at 21. The purpose of this is to providegradually reduced pressure to the material to avoid any sharp line ofdemarcation where adjacent areas are pressed.

Employing my method, eliminating the use of oiled paper over the upperplaten of the press, I have found that there may be some tendency withcertain types of linoleum mix for the particles to adhere to the flaredportion 25 of the upper press platen 24 since, in consolidating pressesas ordinarily constructed, the whole press platen is heated to a hightemperature and insufficient pressure is applied to the particles at theflared portion to consolidate and join them pressing or tend to build upwith other particles on the nose of the press. I have found that thismay be overcome by providing cooling coils in the nose of the press asshown by the dotted lines 28 in Figure 2. These may be in theform ofpassageways or conduits through which brine, cold water,-or othercooling medium may be passed. Since there is some conduction of heatfrom the main portion 4 of the platen to the end portion 23, there willbe a gradual reduction in temperature from the point where the nose 23joins the main platen 24 outwardly toward the lip of the press. I preferto maintain a temperaturebelow about 160 F. in the nose for at suchtemperature there is no lifting of particles. i

From the foregoing, it will be understood that by this invention Ieliminate the need for the application of oiled paper or other facingsto the initial or final consolidating presses and provide an arrangementwhereby the lubricant maybe applied directly to the upper surface onlyof the particles to be engaged by the pressing surface in the initialheat consolidation. The carrier for the lubricant may be reusedindefinitely and there is no offsetting or picking up of particles ofcomposition or stripping off of a skin of material as is common whenoiled paper is used under the initial consolidating press.

While I have illustrated and described certain preferred embodiments ofmy invention, it will be understood that my method is not limited to theembodiment shown and described but may be otherwise embodied andpracticed within the scope of the following claims.

I claim:

1. In the manufacture of molded inlaid linoleum and the like, the stepsof bringing a flat surface carrying a lubricant into engagement with aloose mass of granulated composition to transfer a film of saidlubricant to the upper surface only of the mass of the composition, saidlubricant being applied prior to initial heat consolidation, moving saidcomposition to an initial consolidation station and there applying heatand pressure to said composition with the lubricated surface of saidgranules in direct contact with the pressing surface.

2. In the manufacture of inlaid linoleum and the like, the steps ofbringing a surface coated with a lubricant into engagement with anunconsolidated mass-of granulated composition under pressure sufficientto transfer a thin film of said lubricant to the uppersurface only ofthe mass and insufiicient to cause said particles to adhere to thelubricant coated pressing surface and thereafter applying heat andpressure to said granules with the lubricated surface of the granules indirect contact with the pressing surface to efiect initial heatconsolidation of said composition.

3. In the manufacture of molded inlaid linoleum and the like from aloose mass of granulated composition, the steps of pressing a flat,unheated surface carrying a lubricant into engagement with a mass ofloose granulated composition to transfer a film of said lubricant to theupper surface only of the mass of composition, said lubricant beingapplied prior to initial heat consolidation, and thereafter applyingheat in the order of 350 F. and pressure to said granules to effectinitial heat consolidation of the granules with the lubricated surfaceof said granules in direct contact with the pressing surface with theapplied lubricant serving as the sole means for preventing adhesionbetween the granules and the heated pressing surface.

4. In the manufacture of molded inlaid linoleum and the like from a,loose mass of granulated inlaying composition, the steps of bringingapressing surface coated with a lubricant from above a layer ofgranulated inlaying composition deposited upon a. backing intoengagement with the upper surface only of said layer to transfer a smallamount of lubricant to the loose particles disposed at the upper surfaceof said layer, said lubricant being applied prior to initial heatconsolidation, elevating said pressing surface away from said layer, andthereafter applying heat and pressure to said granules with thelubricated surface of said granules in direct contact with the heatedpressing surface to effect initial heat consolidation of the inlayingcomposition into a homogeneous wearing layer. I

5. In the manufacture of molded inlaid linoleum and the like from aloose mass of granulated composition applied to a backing, the steps ofintermittentlyapplying a, lubricant to the upper surface only ofparticles of granulated composition disposed on said backing, saidlubricant being applied priorto initial heat consolidation, and

intermittently applying heat and pressure to the mass of granulatedcomposition disposed on the backing to effect initial heatconsolidation, with the area under consolidation lying contiguous to anunconsolidated but lubricated area to be subsequently consolidated, saidheat and pressure being applied substantially uniformly throughout theextent of the area under consolidation, except in a narrow zone adjacentthe contiguous, lubricated area to be subsequently consolidated Where aforce is applied gradually diminishing from that applied to the majorarea and where the granules are heated to a lesser degree.

6. In the manufacture of molded inlai linoleum and the like from a loosemass of granules of linoleum composition having a heat sensitiveoilresin binder, said granules being disposed upon a backing web in theform of an unconsolidated layer, the steps of intermittently applyinglubri cant to the upper surface only of the particles of granulatedlinoleum composition to be engaged by a pressing surface, said lubricantbeing applied prior to initial heat consolidation, intermittently movingsaid web with the lubricated granules to an initial heat consolidationstation and there applying pressure to said lubricated granules with aflat heated pressing surface, said heat and pressur being appliedsubstantially uniformly throughout the extent of the area underconsolidation except in a narrow zone adjacent anunconsolidated portionof the layer where a force is applied gradually diminishing from thatapplied in the major area and where the granules are heated to a lesserdegree, and thereafter consolidating the granules in said narrow zonewith the application of greater heat and higher pressure than initiallyapplied in said zone,

'7. In the manufacture of molded inlaid linoleum and the like from aloose-mass of granulated composition, the steps of pressing a fiatforaminous surface wetted with a lubricant into engagement with a massof loose granulated composition to transfer a film of said lubricant tothe upper surface only of the mass of composition, said lubricant beingapplied prior to initial heat consolidation, and thereafter applyingheat and pressure to said granules with the lubricated surface of thegranules in direct contact with the pressing surface to effect initia1heat consolidation of said composition.

8. In the manufacture of molded inlaid linoleum and the like from aloose mass of granulated composition, the steps of pressing a flatsurface carrying paraffine oil into engagement with a mass of loosegranulated composition to transfer a film of said parafiine oil to theupper surface only of the mass of composition, said paraffine oil beingapplied prior to initial heat consolidation, and thereafter applyingheat and pressure to said granules with the paraffine coated granules indirect contact with the pressing surface to effect initial heatconsolidation of said composition.

9. In the manufacture of molded inlaid linoleum and the like from aloose mass of granulated REFERENCES CITED The following references areof record in the file of this patent:

UNITED .STATES PATENTS Number Name Date 425,875 Godfrey et a1 Apr. 15,1890 1,305,127 Lawson May 27, 1919 1,850,630 Kaufman Mar. 22, 19322,299,066 Berger Oct. 20, 1942 308,508 McFerran Nov. 25, 1884

